Fix server shutdown on Windows 7 and 8

std::condition_variable is broken there

Author: botder

Server/mods/deathmatch/logic/CGame.cpp

@@ -422,6 +422,7 @@ CGame::~CGame()
     SAFE_DELETE(m_pASE);
     SAFE_RELEASE(m_pHqComms);
     CSimControl::Shutdown();
+    CThreadPool::getDefaultThreadPool().shutdown();
 
     // Clear our global pointer
     g_pGame = NULL;

Shared/sdk/SharedUtil.ThreadPool.h

@@ -71,26 +71,35 @@ namespace SharedUtil
             return res;
         }
 
-        ~CThreadPool()
+        void shutdown()
         {
+            if (m_exit)
+                return;
+
+            // Ensure every thread receives the exit state, and discard all remaining tasks.
+            {
+                std::unique_lock<std::mutex> lock(m_mutex);
+                m_exit = true;
+
+                while (!m_tasks.empty())
+                {
+                    // Run each task but skip execution of the actual function (-> just delete the task)
+                    auto task = std::move(m_tasks.front());
+                    task(true);
+                }
+            }
+
             // Notify all threads to exit
-            m_exit = true;
             m_cv.notify_all();
+
             // Wait for threads to end
             for (std::thread& worker : m_vecThreads)
-            {
                 worker.join();
-            }
-            // Cleanup
-            do
-            {
-                if (m_tasks.empty())
-                    break;
-                // Run each task but skip execution of the actual
-                // function (-> just delete the task)
-                auto task = std::move(m_tasks.front());
-                task(true);
-            } while (true);
+        }
+
+        ~CThreadPool()
+        {
+            shutdown();
         }
 
         static CThreadPool& getDefaultThreadPool()